diff --git a/tests/test_internal.c b/tests/test_internal.c
index 004dc6f..ee833a3 100644
--- a/tests/test_internal.c
+++ b/tests/test_internal.c
@@ -19,6 +19,7 @@
 
 #include "../src/gmio_core/internal/byte_codec.h"
 #include "../src/gmio_core/internal/byte_swap.h"
+#include "../src/gmio_core/internal/safe_cast.h"
 #include "../src/gmio_core/internal/string_parse.h"
 
 #include "stream_buffer.h"
@@ -56,6 +57,17 @@ const char* test_internal__byte_codec()
     return NULL;
 }
 
+const char* test_internal__safe_cast()
+{
+#if GMIO_TARGET_ARCH_BIT_SIZE > 32
+    const size_t maxUInt32 = 0xFFFFFFFF;
+    UTEST_ASSERT(gmio_size_to_uint32(maxUInt32 + 1) == 0xFFFFFFFF);
+    UTEST_ASSERT(gmio_size_to_uint32(0xFFFFFFFF) == 0xFFFFFFFF);
+    UTEST_ASSERT(gmio_size_to_uint32(100) == 100);
+#endif
+    return NULL;
+}
+
 const char* test_internal__string_parse()
 {
     const char text[] =
@@ -127,6 +139,7 @@ const char* all_tests()
     UTEST_SUITE_START();
     UTEST_RUN(test_internal__byte_swap);
     UTEST_RUN(test_internal__byte_codec);
+    UTEST_RUN(test_internal__safe_cast);
     UTEST_RUN(test_internal__string_parse);
     return NULL;
 }